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(NoModel') '0. FREDERICK an o. N. TRUMP.

PNBUMATI HAMMER. No. 348,837'. Patented sept. 7, 1886.

`are provided.

UNITED STATES PATENT OEEICE.

CHRISTIAN FREDERICK AND CHARLES N. TRIIMP, OF IVILMINGTON, DEL.

PNEUMATIC HAMMER.

SPECIFICATION forming part; of Letters Patent No. 348,837. dated September 7. 1886.

Application filed December 10, i885. Serial No. 185.223. (No model.)

To @ZZ whom it may concern.-

Beit known that we, CHRISTIAN FEEDER- Ick and CHARLES N. TRUMP, citizens of the United States, residing at Vilmington, in the county of New Castle and State of Delaware, haveinvented certain new and useful Improvements in Pneumatic Hammers; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings.

The object of our invention is to provide an improved percussion-tool or pneumatic ham- Iner, the combined hammer-piston striking a tool-holder with anvil-head either within or outside of the cylinder, the anvil being retracted to position for receiving other blows. by direct hand pressure on the tool in use, or by spring or other appropriate means.

The implement furnished with proper bits can be used for drilling and cutting stone, carving wood, engraving, chipping, riveting, and caulking iron, steel, and other metals, and combines in a simple compact form in one tool the means for effectually performing a wide range of work. Compressed air or other elastic medium under pressure can be used as motive force.

In the drawings, Figures l, 2, and 3 represent longitudinal sections of different forms of our device, and Figs. 4c and 4; a device for regulating the force of the blow.

Like letters indicate corresponding parts in all the figures.

Ais the cylinder; B, the piston and hammer, to the head of which is attached a guide-rod, D, extending through cylinder-head E, and serving to reduce the effective pressure area of the driving end of the piston to less than that of the reversing end.4 In Fig. 3 this guide rod works through a splined thimble, U, and thus furnishes means 'for turning the piston in the cylinder either automatically or by hand. The driving agent is admitted through inlet G. Transmission-port H and exhaust-port I The piston opening and closing these ports, valves are unnecessary, although, as shown in Figs. 2 and 3, a pistonvalve is added, by means of which a supplementary exhaust-port is opened and closed automatically for the purpose of relieving the advancing piston from excessive back-pressure.

The lower end of cylinder, Figs. 1 and 3, is closed by head F, bored ont to receive toolholder C L, the anvil-head C being within the cylinder. In Fig. 2 the piston is provided with elongated hammer end e, which passes through head F, and strikes the anviLheaded tool-holder carried in external case, R; or the end c may be still farther extended, and having properly-constructed bits attached, and the guide-rod D furnished with spiral groove and ratchet-thimble (or other suitable device) for turning the piston automatically during the reverse movement. used for drilling rock.

The tool-holder C L is provided with chuck or equivalent mechanism for holding the bit or tool to be used, its enlarged header anvil C fitting the case S. After receiving a blow from the hammer the anvil is retracted to position for receiving other blows by a spring coiled around the body of tool-holder by compressed air admitted to case S through small port X, connecting it with cylinder A, or by direct pressure of the hand on the bit in use. A wide keyway is cut longitudinally through the tool-holder and casing, (shown in crosssection in Fig. l, and side view in Fig. 8,) and a narrow key, M, inserted under a ca1n ring N, having spirally-inelined edges, with which the ends of the key projecting beyond the easing engage. This device is'shown in detail in Figs. 4 and 4, By turning ring N and confining it when properly placed by a thumb set screw the anvil may be drawn more or less away from the blows of the hammer and the force of the blow regulated at will. A collar, Q, as shown in Fig. 2, screwed on over the casing and engaging with a collar, V, on projecting shank of tool-holder, may be used for the same purpose.

Inlet G, Fig. l, is furnished with a cock for regulating the supply of air. To guard against the piston stopping in position to close both transmission and exhaust ports,a supplementary passage, f, Fig. l, is provided, leading from the air-supply to transmission passage, the

The implement may be key of the cock having a second air-port, so that as the key is turned air passes to the hammer end of the cylinder, forcing the piston back, so as to uncover the exhaust-port before air is admitted to the driving end of the piston through the main opening in the key.

Exhaust-port I should open into a tube, y, so placed as to direct the escaping air upon the work to remove dust. A series of exhaust-ports, as l 2 3, may be made and covered with a sliding piece or a second tube fitted inside of 1 through which openings are made corresponding to exhaust-ports 1, 2, and 3, so that when the inner tube is turned by a key either one of the exhaust-ports shall communicate with the directing-tube, and exhaust takes place when the piston on its reverse movement passes the port which is open.

Piston B, Fig. 3, has slots or recesses T T T cut in its surface, terminating at different distances from its upper end. By means of splined thimble U, through which guide-stem D works, the piston may be turned so that either of the slots will, in connection with the walls of the cylinder, form a connecting-passage between ports H and p at the termination of the reverse movement.

Piston-valve a, Fig. 3, is a reduced copy of B, Fig. l, in that its two surfaces are of unequal area. The chamber in which it works is connected with main cylinder by small ports o and p. The valve is connected with tubular valve b, actuating it to open and close reliefport t'.

Vhen valve a is used, the twoway cock is not required and exhaust I is not essential, though advantageous when working the hammer full stroke, or when a groove is turned in the surface of piston in place of slot T, as indicated by dotted lines, and when the device is used as a rock-drill.

A suitable bit or chisel being fastened in the tool-holder and the implement placed in position by the operator using compressed air for motor, the action is as follows: As the key of the cock is turned to admit the driving agent a puff at -full pressure passes through the smaller opening in it to the ham mer end of the cylinder, insuring the proper position of the piston for starting. The opening movement of the key being continued the air admitted drives piston B forward, causing the hammerlface to strike anvil C. Port H being uncovered, compressed airis transmitted to the lower end of the cylinder, and,acting upon thelarger area of the hammer end of the piston, reverses the movement. Vhen exhaust-port I is uncovered, the partially-expanded medium escapes and the piston is again driven forward. Valve a, Fig. 3, in action opens relief-port t', allowing air to escape from the cylinder in front of the advancing piston. Air at full pressure entering the small chamber above the valve forces it forward, carrying with it tube b and uncovering relief-port t'. When the upper end of B passes port p, air at full pressure enters the chamber under valve a, and by reason of the greater area of that end of the valve forces it back, closing relief-port t', thus confining the air requisite to cushion the piston. While still moving forward, as described above, the blow is delivered, and port H being simultaneously uncovered the movement of the piston is reversed. Vhen the upper end of slot T passes p, communication is open between valve-ch amber and lower end of cylinder, and the air in that being partially expanded or at normal pressure by reason of the opening of exhaustport I, valvea is again driven forward and the movement of the hammer-piston repeated.

Ve are aware that cylinders without valves of the form herein described have been used for rock-drilling, and we do not broadly claim such forms; but,

Having described our invention, what we do claim, and desire to secure by Letters Patent, is-

l. In a pneumatic hammer, a cylinder of uniform diameter with transmission and eX- haust ports, a hammer piston fitted to the cylinder and adapted to control the valves, with 4extension-rod l) passing through cylinder-head, serving toreduce the effective area of driving end of piston, in combination with anvil-headed tool-holder or tool carried in case formed in cylinder-head next hammer end of piston or attached thereto, substantially as described.

2. In a pneumatic hammer or percussiontool, the combination, with chamber or chambers provided with transmission and exhaust ports and piston fitting thereto, of an auxiliary valve-chamber, and communicating ports o p, piston-valve a, tube-valve b, connected thereto, relief -port i, and recess or slots in surface of piston forming connecting passages between p and H when reverse movement of piston is completed,substantially as described.

3. In a pneumatic hammer, an anvil-headed tool holder and case in which it reciprocates, a port connecting the case with the main hammer-cylinder to admit compressed air below the anvil -head on the reverse movement of the hammer, so as to assist in retracting the anvil into position for receiving blows from the hammer, substantially as described.

4. In a pneumatic hammer, the combination of tool-holder provided with wide longitudinal keyway, a narrow key, and a spiral-edged cam-adjusting ring engaging the ends of the key, whereby the force of the blow may be regulated, `substantially as described.

5. In a pneumatic hammer, a series of exhaust-"p'ortsY covered by a slide or slides or opening into a tube, provided with an inner tube movable therein and having openings corresponding with each of the exhaust-ports,

IIO

so that when the slide or tube is Mset ex- In testimony whereof we aiiix our signatures haust may occur through either of the ports, in presence of two Witnesses. as may be desired, substantially as described.

6. In apneumatic hammer, the combination CHRISTIAN FREDERICK. 5 of the cylinder, transmission-port, and two- CHARLES N. TRUMP.

Way cook adapted to admit the driving agent to the hammer end of cylinder', so as to eom- Vitnesses: plete the reverse movement of the piston be- GEo. R. HoEEEoKER, fore airis admitted to the driving end, sub- WILLIAM FREDERICK.

1o stantiaily as described. 

